CRYOMAGNETICS 4G - Appendix B: Computer Interface Command Reference

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Cryomagnetics Model 4G Operating Instruction Manual 39

Appendix B: Computer Interface Command Reference

Commands available over the computer interface are identified by availability. Commands that are

available only when the operational display is active are noted as "Operate", commands that require

remote mode are noted as "Remote". All queries and IEEE-488.2 specific commands are always

available, regardless of whether the state is Local, Remote, or unassigned. Commands that are

IEEE 488.2 specific can be recognized by an asterisk (*) as the first character. All command

mnemonics that elicit a response from the instrument (referred to as queries) end with a question

(?) character. A general command format is as follows:

where a subcommand is formatted

Example:

*IDN?;*ESE 12;*ESE?<RETURN>

Responses to each subcommand are separated by semicolons. The above example would return:

Cryomagnetics,4G,2239,1.14,245;12 <RETURN><LINEFEED>

where the serial number is 2239 and the firmware version number is 1.14,245.

Error Handling and Command Availability

The ERROR command allows error messages to be enabled or disabled when the RS-232 interface

is used. The IEEE-488.2 status mechanisms may always be used to determine if an error occurred

processing a command, and the category of the error. Some commands are unavailable if the

instrument menu is being accessed by an operator at the instrument, or if the instrument is in

LOCAL mode. If a command available only in operate mode is received while the menus are being

accessed, or if a command available only in remote mode is received while not in remote mode, a

device dependent error is reported in the Extended Status Register (ESR), and the message

"Command blocked" will be returned if error reporting is enabled when using the RS-232 interface.

Table 2 lists the 4G commands, shows the modes where they may be used, and provides a short

command description. Command details are provided in the following reference.